CBSE Class 8 Science Practice Paper 2026 with Answer Key (Set 1) – Ultimate Exam Preparation Guide

Introduction

Preparing for the CBSE Class 8 Science exam becomes much easier when students practice with well-designed question papers that follow the latest exam pattern. The CBSE Class 8 Science Practice Paper 2026 with Answer Key (Set 1) on a2zly.com has been created to help students strengthen their concepts and familiarize themselves with the CBSE Class 8 Science Practice Paper 2026, improve answer-writing skills, and understand how questions may appear in the final examination.

This practice paper is carefully structured according to the CBSE syllabus and NCERT guidelines, covering important chapters. By solving this paper, students can evaluate their preparation level, identify weak areas, and build confidence before their exams.

Practicing with the CBSE Class 8 Science Practice Paper 2026 will also aid students in becoming adept at handling different question formats and enhance their problem-solving abilities.

By using the CBSE Class 8 Science Practice Paper 2026, students will learn how to manage their study time effectively, ensuring they cover all necessary topics before the exam.

The included detailed answer key allows students to check their responses instantly and learn the correct way to present answers in the examination. Whether you are revising the syllabus or testing your knowledge through self-assessment, this practice paper from a2zly.com will serve as an effective study resource for achieving better results in the CBSE Class 8 Science Exam 2026.

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MODEL QUESTION PAPER – 2026

Subject: Science          Class: VIII             Maximum Marks: 60           Time: 2½ Hours SET 1

GENERAL INSTRUCTIONS

1. All questions are compulsory. Internal choices are provided in some questions.

2. Section A contains 10 MCQs and 2 Assertion–Reason questions of 1 mark each.

3. Section B contains 6 questions of 2 marks each.

4. Section C contains 6 questions of 3 marks each.

5. Section D contains 2 case-based questions of 4 marks each.

6. Section E contains 2 long answer questions of 5 marks each.

7. Draw neat and properly labelled diagrams wherever required.

SECTION – A (1 × 12 = 12 marks)

(Multiple Choice Questions)

Q1. When air is heated, it becomes: (a) Heavier and moves downward (b) Lighter and rises upward (c) Denser and remains in place (d) Colder and heavier

Answer: (b) Lighter and rises upward

Explanation: Heating causes air particles to gain energy, move faster, spread apart → density decreases → air becomes lighter and rises (convection current).

Q2. Which state of matter has a definite volume but no definite shape? (a) Liquid (b) Solid (c) Plasma (d) Gas

Answer: (a) Liquid

Explanation: Liquids take the shape of the container (no definite shape) but have fixed volume due to close particle packing.

Q3. Which of the following is a mixture? (a) Oxygen (b) Water (c) Air (d) Sodium chloride

Answer: (c) Air

Explanation: Air is a homogeneous mixture of gases (N₂ ~78%, O₂ ~21%, etc.). Oxygen, water (H₂O), and NaCl are pure substances (element/compound).

Q4. Friction can be reduced by: (a) Making the surface rough (b) Applying oil or grease (c) Increasing the weight (d) Pressing the surfaces harder

Answer: (b) Applying oil or grease

Explanation: Lubricants like oil/grease form a slippery layer, reducing contact between surfaces → less friction.

Q5. A leap year in the Gregorian calendar has: (a) 364 days (b) 365 days (c) 366 days (d) 360 days

Answer: (c) 366 days

Explanation: Leap years have 366 days (extra day in February) to align calendar with solar year (~365.2425 days).

Q6. Which of the following represents parasitism? (a) Bird eating insects on a buffalo (b) Tick on a dog (c) Lichen (d) Bees pollinating flowers

Answer: (b) Tick on a dog

Explanation: Parasitism: one organism (parasite = tick) benefits while harming the host (dog). Option (a) is mutualism/commensalism; (c) lichen is mutualism; (d) mutualism.

Q7. Which instrument is used to measure wind speed during a cyclone? (a) Barometer (b) Thermometer (c) Anemometer (d) Seismograph

Answer: (c) Anemometer

Explanation: Anemometer measures wind speed. Barometer → pressure; thermometer → temperature; seismograph → earthquakes.

Q8. Which of the following statements is true about gases? (a) Gases have a fixed volume (b) Gases can be compressed easily (c) Gases have a definite shape (d) Gases have very strong intermolecular forces

Answer: (b) Gases can be compressed easily

Explanation: Gases have weak intermolecular forces, large spaces between particles → easily compressible. No fixed shape/volume; weak forces.

Q9. A woman walks towards a large convex mirror in a museum. She observes that: (a) Her erect image becomes smaller (b) Her inverted image becomes smaller (c) Her inverted image increases in size and later becomes erect and magnified (d) Her erect image increases in size

Answer: (a) Her erect image becomes smaller

Explanation: Convex mirrors always form virtual, erect, diminished images. As she approaches, image size increases but remains smaller than object and erect.

Q10. In commensalism, the host organism is: (a) Harmed (b) Benefited (c) Killed (d) Neither benefited nor harmed

Answer: (d) Neither benefited nor harmed

Explanation: Commensalism: one organism benefits (+), host unaffected (0), e.g., remora on shark.

Choose the correct option:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true

Q11.

Assertion (A): The solubility of a gas in a liquid increases when the pressure on the gas increases.
Reason (R): Higher pressure pushes more gas molecules into the liquid.

Answer: (a) Both A and R are true and R is the correct explanation of A.

Explanation:
According to Henry’s Law, the solubility of a gas in a liquid increases with an increase in pressure. When pressure increases, more gas molecules are forced into the liquid, increasing their dissolution.

Q12.

Assertion (A): Irrigation is necessary for healthy crop growth.
Reason (R): Water helps plants absorb nutrients from the soil and supports photosynthesis.

Answer: (a) Both A and R are true and R is the correct explanation of A.

Explanation:
Water is essential for transporting nutrients, maintaining plant structure, and carrying out photosynthesis, which helps plants grow properly.

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SECTION – B (2 × 6 = 12 marks)

Short Answer Questions – I (2 × 6 = 12 marks)

Q13. A rubber sucker is pressed on a smooth flat surface, and another identical sucker is pressed on a rough surface. In which case will it be easier to pull off the sucker? Give a reason.

Answer: Easier to pull off from the rough surface.

Reason: On a smooth surface, the sucker creates a better airtight seal (almost no air enters underneath) → strong vacuum (low pressure inside) → atmospheric pressure holds it firmly. On a rough surface, air leaks in through gaps → less vacuum → easier to pull off.

Q14. Why does ocean water taste salty even though salt is not visibly present? Explain.

Answer: Ocean water tastes salty because it contains dissolved salts (mainly sodium chloride) and other minerals.

Explanation: Rivers carry dissolved salts/minerals from rocks/soil into oceans over millions of years. Water evaporates (leaving salts behind) → concentration increases → salty taste, though salts are dissolved (not visible as particles).

Q15. What is corrosion? How can it be prevented?

Answer: Corrosion is the slow eating away/deterioration of metals due to reaction with air, moisture, or chemicals (e.g., rusting of iron).

Prevention methods:

• Painting/greasing/oiling the surface (barrier against moisture/air)
• Galvanization (coating iron with zinc)
• Alloying (e.g., stainless steel)
• Using sacrificial metals (e.g., magnesium in cathodic protection)

Q16. A metal cube has a mass of 540 g and a volume of 60 cm³. Calculate its density. Compare it with the density of water (1 g/cm³) and state whether it will float or sink in water. Give reason.

Answer: Density = Mass / Volume = 540 g / 60 cm³ = 9 g/cm³

Comparison & conclusion: Density (9 g/cm³) > density of water (1 g/cm³) → it will sink in water.

Reason: Objects sink if their density is greater than water’s (more mass per unit volume → greater downward force than buoyant force).

Q17. Draw a ray diagram to show the formation of image by a plane mirror. State any two characteristics of the image formed.

Answer:

Two characteristics:

1. Image is virtual and erect.
2. Image is laterally inverted (left-right reversed) and same size as object.

Q18. What are producers, consumers and decomposers? Give one example of each.

Answer:

• Producers: Autotrophs that make their own food (via photosynthesis). Example: Green plants (grass).
• Consumers: Heterotrophs that depend on others for food. Example: Lion (carnivore) or deer (herbivore).
• Decomposers: Break down dead organisms/wastes into simpler substances. Example: Bacteria or fungi (mushroom).

SECTION – C (3 × 6 = 18 marks)

Short Answer Questions – II (3 × 6 = 18 marks)

Q19. Compare solids, liquids, and gases based on: (i) Arrangement of particles (ii) Force of attraction between particles (iii) Shape and volume

Answer:

Property	Solids	Liquids	Gases
(i) Arrangement of particles	Closely packed, fixed positions (ordered)	Close but can slide past each other	Far apart, random motion
(ii) Force of attraction	Very strong	Weaker than solids	Very weak / negligible
(iii) Shape and volume	Definite shape and volume	No definite shape, definite volume	No definite shape or volume

Q20. Differentiate between the mantle and the core of the Earth. (Any three points)

Answer:

Feature	Mantle	Core
Location	Between crust and core (thickest layer)	Innermost layer
Composition	Mainly silicate rocks rich in iron/magnesium	Outer core: liquid iron-nickel; Inner core: solid iron-nickel
State	Semi-solid (plastic-like, flows slowly)	Outer: liquid; Inner: solid
Temperature	500–4000°C	Up to ~6000°C (hottest)

Q21. Why are convex mirrors used as rear-view mirrors in vehicles?

Answer: Convex mirrors are used because:

1. They form erect (upright) images.
2. They form virtual images.
3. They provide a wider field of view (diminished image → more area visible).
4. They help judge distances better (objects appear smaller/farther → reduces accidents).

Q22.

A. Draw the following phases of the Moon: (a) Crescent Moon (b) New Moon

B. What is meant by the waxing phase of the Moon?

Answer:

A.

• Crescent Moon: Thin illuminated sliver on one side (e.g., right side in waxing crescent), rest dark.
• New Moon: Completely dark (no visible illuminated part, Moon between Earth and Sun).

B. Waxing phase: The phase when the illuminated portion of the Moon visible from Earth gradually increases (from new moon → crescent → quarter → gibbous → full moon).

Q23. What is the greenhouse effect? Name two planets where the greenhouse effect is observed.

Answer: Greenhouse effect: Natural process where certain gases (CO₂, methane, water vapour) in atmosphere trap heat from the Sun → warm the planet (essential for life on Earth). Excess causes global warming.

Two planets:

• Venus (extreme greenhouse effect → hottest planet, ~460°C)
• Earth (moderate, keeps average ~15°C)

Q24. How are plants and animals interdependent in an ecosystem?

Answer: Plants and animals depend on each other as follows:

• Plants produce oxygen (photosynthesis) → animals breathe it.
• Animals produce CO₂ (respiration) → plants use it for photosynthesis.
• Plants provide food/shelter → animals (herbivores → carnivores).
• Animals help in pollination, seed dispersal → plant reproduction.
• Decomposers (from both) recycle nutrients.

SECTION – D (4 × 2 = 8 marks)

Case-Based Questions (4 × 2 = 8 marks)

Q25. Rohan heated a small empty tin can with a little water in it. After some time, he quickly closed the lid and poured cold water over the can. (a) What happens to the can after cold water is poured over it? (b) What change occurs in the air pressure inside the can? (c) Explain why this change causes the can to behave in that way.

Answer:

(a) The can gets crushed / implodes (collapses inward).

(b) Air pressure inside the can decreases (becomes much lower than atmospheric pressure outside).

(c) Heating turns water to steam → steam fills can, pushes air out. Closing lid traps steam. Pouring cold water condenses steam back to water (volume decreases drastically) → creates partial vacuum/low pressure inside. Atmospheric pressure outside (higher) crushes the can inward.

Q26. Students observed a diagram showing the Earth revolving around the Sun and the Moon revolving around the Earth. The Moon’s orbit appeared slightly tilted relative to the Earth’s orbit. Based on this observation, answer the following:

A. Which factor mainly prevents eclipses from occurring every month? (i) Rotation of the Earth (ii) Revolution of the Earth (iii) Tilt of the Moon’s orbit (iv) Distance between Earth and the Moon

B. Identify the eclipse that occurs when the Earth comes between the Sun and the Moon.

C. Which type of eclipse occurs on a full moon day and on a new moon day?

Answer: A. (iii) Tilt of the Moon’s orbit

Explanation: Moon’s orbit is tilted ~5° to Earth’s orbit → Sun, Earth, Moon rarely align perfectly → eclipses not monthly.

B. Lunar eclipse (Earth blocks sunlight to Moon).

C. Full moon day → Lunar eclipse (possible). New moon day → Solar eclipse (possible).

SECTION – E (5 × 2 = 10 marks)

Long Answer Questions (5 × 2 = 10 marks)

Q27. Analyse Fig. 8.24. Identify Gas A. Also, write the word equation of the chemical reaction.

Answer: Gas A is hydrogen gas (H₂).

Word equation: Iron + Dilute Hydrochloric acid → Iron chloride + Hydrogen gas

Explanation: (From typical NCERT Fig. 8.24) — Iron filings react with dilute HCl → effervescence (bubbles) of colourless, odourless gas that burns with pop sound → hydrogen. Salt formed is FeCl₂.

Q28.

A. A city has decided to replace traditional public parks with concrete shopping complexes. Discuss how this could affect the local temperature and air quality.

B. Mention any three global campaigns or agreements aimed at reducing carbon emissions and controlling climate change.

Answer:

A.

• Local temperature: Increases (urban heat island effect). Concrete/asphalt absorbs and radiates more heat; no vegetation → less evapotranspiration/cooling → higher temperatures.
• Air quality: Worsens. Fewer plants → less CO₂ absorption, less O₂ production; more vehicles/construction → higher dust, particulate matter, CO₂, NOx, SO₂ → pollution rises, respiratory issues increase.

B. Three global efforts:

1. Paris Agreement (2015) — Nations commit to limit global warming to well below 2°C (preferably 1.5°C), reduce greenhouse gas emissions.
2. Kyoto Protocol (1997) — Binding targets for developed countries to reduce emissions (predecessor to Paris).
3. COP (Conference of Parties) meetings / Net Zero campaigns (e.g., UN-led efforts for carbon neutrality by 2050).

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Conclusion

Regular practice is the key to scoring well in exams. By attempting the CBSE Class 8 Science Practice Paper 2026 with Answer Key (Set 1), students can become familiar with the exam format, improve time management, and strengthen their understanding of important scientific concepts.

Students are encouraged to first attempt the paper independently and then verify their answers using the provided answer key. This method not only helps in self-evaluation but also improves conceptual clarity and confidence.

For more CBSE study materials, practice papers, model question papers, and exam preparation resources, keep visiting a2zly.com. Our goal is to provide students with high-quality, easy-to-understand learning content that supports their academic success.

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For optimal results, integrate the CBSE Class 8 Science Practice Paper 2026 into your study sessions and watch your performance improve.

Remember, consistent practice with the CBSE Class 8 Science Practice Paper 2026 will yield the best outcomes on exam day.